scholarly journals Anatomical and morphological features of seedlings of some Cactoideae Eaton (Cactaceae Juss.) species

2016 ◽  
Vol 69 (4) ◽  
Author(s):  
Halyna Kalashnyk ◽  
Nataliia Nuzhyna ◽  
Maryna Gaidarzhy
Keyword(s):  
Calcium Oxalate ◽  
Vascular Tissue ◽  
Morphological Structure ◽  
Morphological Features ◽  
Vascular Bundles ◽  
Sectional Area ◽  
Cross Sectional ◽  
Arid Conditions ◽  
Pith Parenchyma ◽  
Thin Walled

<p>Three-month-old seedlings of 11 species of the subfamily Cactoideae (<em>Melocactus bahiensis</em>, <em>Melocactus curvispinus</em>, <em>Echinopsis eyriesii</em>, <em>E. mirablis</em>, <em>E. peruviana</em>, <em>Oreocereus celsianus</em>, <em>Rebutia flavistyla</em>, <em>Rebutia minuscula</em>, <em>Astrophytum myriostigma</em>, <em>Mamillaria columbiana</em>, and <em>M. prolifera</em>) have been studied. These plants exhibit a uniseriate epidermis, covered by a thin cuticle. Except for <em>E. peruviana</em> and <em>A. myriostigma</em>, no hypodermis could be detected. The shoots of all studied specimens consist mainly of cortex parenchyma with large thin-walled cells. The pith parenchyma is composed of much smaller cells. Due to the fact that the cortex parenchyma comprises the largest portion of the cross-sectional area, it can be concluded that it is the main water-storing tissue. The extent of vascular tissue development varies. Collateral vascular bundles are present in the stele. The studied seedlings contain various ergastic substances, in particular inclusions of calcium oxalate (all studied species), starch (<em>Mammillaria prolifera</em>, <em>E. mirabilis</em>, and the genus <em>Melocactus</em>), inulin-like inclusions, and occasionally lipid drops (some <em>Echinopsis</em> species).</p><p>Thus, it was found that all studied plants have a highly specialized anatomical and morphological structure. At the same time, the epidermis and hypodermis are poorly developed. Accordingly, the adaptation to arid conditions of the examined seedlings involves an increased growth of the water-storing tissue and the production of ergastic substances.</p>

The degradation of the cell walls of lucerne, Italian ryegrass and wheat straw when fed to cattle, sheep and rabbits

2001 ◽  
Vol 137 (3) ◽  
pp. 337-349 ◽  
Author(s):  
N. AHMAD ◽  
D. WILMAN
Keyword(s):  
Wheat Straw ◽  
Cell Walls ◽  
Cross Sectional Area ◽  
Italian Ryegrass ◽  
Sectional Area ◽  
Cross Sectional ◽  
Plant Parts ◽  
Thin Walled ◽  
Cattle And Sheep

Dried lucerne (Medicago sativa), dried Italian ryegrass (Lolium multiflorum) and wheat (Triticum aestivum) straw, in the latter case supplemented with soyabean meal, were each fed to cattle, sheep and rabbits in each of 2 years. In both years, plant parts of the three diets were tested for in vitro digestibility, in both milled and chopped (1 cm lengths) form, and for cell wall content (as NDF). In the first year, the plant parts were analysed for lignin and both the plant parts and the faeces were examined microscopically for the proportions of thick-walled, thin-walled and epidermal cells in cross-sectional area and for the thickness of the cell walls.The plant parts with the lowest proportion of thick-walled cells in cross-sectional area (0·05) were the lucerne leaflets and those with the highest proportion of thick-walled cells (0·68) were the stems of wheat straw. The cell walls of the thick-walled tissues were thinnest (0·7–0·8 μm) in Italian ryegrass leaf blades and sheaths. Within each cell type for the whole crop, the order of cell wall thickness was wheat straw > lucerne > Italian ryegrass. In vitro digestibility of DM was lower (by 0·031–0·085 g digestible DM/g total DM) in chopped than in milled stems of lucerne, ryegrass and wheat and in leaf sheaths of wheat. This suggests incomplete and/or delayed access of rumen microorganisms to some of the cell wall in chopped material in vitro and probably, therefore, also in chewed material in vivo. The concentrations of NDF and lignin in both ryegrass and wheat were in the order leaf blades < leaf sheaths < stems.The lucerne crops were more mature than the ryegrass crops and there was no consistent difference between lucerne and ryegrass in intake of DM or intake of NDF. The intake of wheat straw DM was 0·52 that of lucerne and ryegrass, whereas the intake of straw NDF was 0·89 that of lucerne or ryegrass NDF. Intake of both DM and NDF in relation to metabolic body weight was highest (87–93 g DM and 45–48 g NDF/kg W0·75) with cattle on lucerne and ryegrass and rabbits on ryegrass and lowest (33–34 g DM and 29–30 g NDF/kg W0·75) with sheep and rabbits on straw. The output of faeces/kg W0·75 was particularly high (38–41 g DM and 30–32 g NDF) from rabbits fed lucerne or ryegrass. Digestibility of DM was highest (0·726–0·732 g/g) with cattle and sheep fed ryegrass, followed by cattle and sheep fed lucerne and sheep fed straw. Digestibility of NDF was highest (0·708–0·752 g digestible NDF/g total NDF) with cattle and sheep fed ryegrass and sheep fed straw. Digestibility of NDF with rabbits was lower than with cattle or sheep, but was higher than might have been expected, in a small, hind-gut fermenter, with ryegrass (0·339 g/g) and straw (0·492 g/g).The proportion of thin-walled cells was much lower in the faeces than in the diets, but there was an appreciable proportion (0·10–0·27) of these cells in the cross-sectional area of faecal particles. The cell walls of all cell types were thinner in the faeces than in the diets, e.g. those of the thick-walled cells were thinner by 0·35 μm in lucerne, by 0·11 μm in Italian ryegrass and by 0·41 μm in wheat straw. The faeces from rabbits had higher proportions of thick-walled and epidermal plant cells in cross-sectional area, and a lower proportion of thin-walled cells, than the faeces from cattle and sheep.

ASME B31.3 End of Life Considerations: Corrosion, Mechanical Strength, and Small Bore Geometry

2010 ◽  
Author(s):  
Dennis K. Williams
Keyword(s):  
Mechanical Strength ◽  
End Of Life ◽  
Longitudinal Direction ◽  
Careful Examination ◽  
Tabular Form ◽  
Sectional Area ◽  
Cross Sectional ◽  
Section Modulus ◽  
Process Piping ◽  
Thin Walled

This paper discusses the prescribed requirements contained within the ASME B31.3 Process Piping Code that specifically address the considerations of the design corrosion allowance when coincidently taken into account with the mechanical strength requirements of the same. In particular, the most significant effects of the least favorable corrosion allowances in combination with the mechanical strength requirements of ASME B31.3 are prevalent in thin walled, small bore piping of minimal geometric properties associated with the calculation of component stresses in the longitudinal direction. Careful examination of ASME B31.3 paragraph 302.4 reveals that the minimum required thickness of a piping component include allowances for corrosion and when taken in conjunction with paragraph 302.4.1, which requires that when necessary, the wall thickness shall be increased to prevent overstress, damage, or collapse, due to superimposed loads from handling or other causes. The effects of the aforementioned Code requirements are addressed and examples are presented for small bore piping (nps 2″ and below) that lead to a proposed small bore piping criteria for consideration by piping specification engineers. Finally, the results of the evaluation of various combinations of corrosion allowance and mechanical strength requirements in terms of metal cross sectional area and section modulus are presented in tabular form that support the proposed small bore piping criteria.

Physical strength and its relation to leaf anatomical characteristics of nine forage grasses

2004 ◽  
Vol 52 (6) ◽  
pp. 799 ◽  
Author(s):  
Ji Min Zhang ◽  
Akio Hongo ◽  
Masahiro Akimoto
Keyword(s):  
Shear Strength ◽  
Festuca Arundinacea ◽  
Dactylis Glomerata ◽  
Cross Sectional Area ◽  
Vascular Bundles ◽  
Sectional Area ◽  
Forage Grasses ◽  
Cross Sectional ◽  
Anatomical Characteristics ◽  
Physical Strength

Nine species of forage grasses (five C3 species and four C4 species) were planted in a controlled-environment glasshouse. The C3 plants were Festuca arundinacea Schreb, Dactylis glomerata L., Phleum pratense L., Lolium perennel L. and Poa pratensis L.; the C4 plants were Chloris gayana Kunch., Cynodon dactylon (L.) Pers., Paspalum dilatatum Poir. and Sorghum halenpense (L.) Pers. The number of major vascular bundles and minor vascular bundles, cross-sectional area, the area and proportion of sclerenchyma in a cross-section, thickness of leaf blade, and tensile and shear strength were investigated in order to determine the relationship between physical strength and anatomical characteristics. Physical strength and anatomical characteristics of leaf blades showed significant (P < 0.01) variation between species. Significant correlations were detected between tensile strength and cross-sectional area in forage grasses except Festuca arundinacea. Festuca arundinacea, Dactylis glomerata, Phleum pratense, Chloris gayana and Sorghum halenpense showed significant correlations of tensile strength with the number of major vascular bundles. Festuca arundinacea, Dactylis glomerata and Lolium perennel showed significant correlations of shear strength with cross-sectional area. Festuca arundinacea, Dactylis glomerata and Paspalum dilatatum showed significant correlations of shear strength with the number of major vascular bundles. The proportion of sclerenchyma in a cross-section showed poor correlations with tensile and shear strength. Thickness of leaf blade showed poor correlations with tensile and shear strength except in Dactylis glomerata. Physical strength and anatomical characteristics of leaf blades of the C3 group differed significantly (P < 0.01) when compared with the C4 group except for cross-sectional area. Tensile and shear strength showed significant correlations with cross-sectional area, sclerenchyma area and the number of vascular bundles when all nine species were treated as one group.

scholarly journals MARCADORES ANATÔMICOS DO PECÍOLO E A TOLERÂNCIA À SECA DE PONTEIROS E AO DÉFICIT HÍDRICO EM EUCALIPTO

Nativa ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 591-596
Author(s):  
Samyra Alves Condé ◽  
Edgard Augusto de Toledo Picoli ◽  
Thais Roseli Corrêa ◽  
Rodrigo Dal Sasso Lourenço
Keyword(s):  
Water Stress ◽  
Vascular Tissue ◽  
Relevant Information ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Physiological Disorder ◽  
Cross Sectional ◽  
Water Nutrients ◽  
Different Levels ◽  
Selection Of

A seca de ponteiros em Eucalipto é um distúrbio fisiológico, onde o estresse hídrico vem sendo associado como um dos fatores intensificadores de sua ocorrência. A seleção precoce de genótipos de eucalipto tolerantes a essas condições, podem fornecer informações relevantes quanto a esse distúrbio. Objetivou-se avaliar possíveis marcadores anatômicos, associados a tolerância ao déficit hídrico e à seca de ponteiros. Genótipos comerciais com diferentes graus de suscetibilidade a seca de ponteiros foram submetidos a diferentes níveis de estresse hídrico em condições de casa de vegetação. A duração do experimento foi de 75 dias. Amostras de pecíolos foram coletadas e avaliadas as características das áreas anatômicas de: seção transversal, tecido vascular, xilema, floema e do córtex. Os dados foram submetidos à análise da variância (ANOVA) e para comparação de médias foi adotado o teste Tukey (p<0,05). Os resultados mostraram que há a tendência de redução de todas as variáveis avaliadas com o aumento do déficit hídrico. Entretanto, o genótipo tolerante em condições de maior restrição hídrica apresenta maior área de seção transversal e de tecidos condutores em comparação ao suscetível. A maior proporção destes tecidos sugere que o clone tolerante apresenta condição mais favorável ao transporte de água, fotoassimilados e nutrientes. Palavras-chave: melhoramento florestal; silvicultura; seleção genômica.   ANATOMICAL MARKERS OF PETIOLE AND TOLERANCE TO DIE-BACK AND WATER STRESS IN EUCALYPTUS   ABSTRACT: Die-Back in Eucalyptus is a physiological disorder where the water stress has been associated as an intensifier of this occurrence. The early selection of tolerant Eucalyptus genotypes to water stress can provide relevant information to this disorder. The research aimed to evaluate possible anatomical markers associated with tolerance to water stress and Die-Back. Commercial genotypes with different levels of susceptibility to this disorder were submitted to different levels of water stress in a greenhouse condition. The experiment lasted 75 days. Petioles samples were collected and anatomical characteristics were evaluated: cross-sectional area, area of vascular tissue, xylem area, phloem area and cortical area. The data were submitted to analysis of variance (ANOVA) and for the comparison of means was adopted Tukey test (p <0.05). The results show us that there is a tendency to reduce all variables with increasing water deficit. However, the tolerant genotype in higher water stress conditions has greater cross-sectional area and conducting tissues compared to susceptible genotype. The major proportion of these tissues suggests that the tolerant clone presents more favorable condition for transport of water, nutrients and assimilates. Keywords: forest improvement; forestry; genomic selection.

Morphometric analysis of Rhynia and Asteroxylon: testing functional aspects of early land plant evolution

Paleobiology ◽  
2000 ◽  
Vol 26 (3) ◽  
pp. 405-418 ◽  
Author(s):  
A. Roth-Nebelsick ◽  
G. Grimm ◽  
V. Mosbrugger ◽  
H. Hass ◽  
H. Kerp
Keyword(s):  
Water Transport ◽  
Land Plant ◽  
Plant Evolution ◽  
Cross Sectional Area ◽  
Land Plants ◽  
Limiting Factor ◽  
Vascular Bundles ◽  
Sectional Area ◽  
Cross Sectional ◽  
Early Land

New morphometric data gathered from cross-sections of two Lower Devonian land plants (Rhynia gwynne-vaughanii and Asteroxylon mackiei) are interpreted in terms of the evolution of the function of vascular bundles in early land plants. The following conclusions can be drawn from these new data: (1) The ratio of the cross-sectional area of the xylem (representing the conducting volume supplying the axis with water) to the xylem perimeter (representing the “contact area” between xylem and parenchyma through which water leaves the xylem and enters the parenchyma) is not constant for Rhynia axes, almost constant for Asteroxylon axes, and different between Rhynia and Asteroxylon. Thus, Bowers hypothesis that the ratio of cross-sectional area of the xylem to xylem perimeter is constant during ontogenetic development is true for Asteroxylon. That this ratio is constant during phylogeny, however, is not supported by our data. (2) The ratio between cross-sectional area of xylem to parenchyma is higher in Asteroxylon than in Rhynia. (3) As predicted by previous computer simulations, the ratio of the xylem perimeter to the axis perimeter plays a major role in determining water transport performance of the transpiring axis. This ratio is constant within ontogeny but is different in Asteroxylon and Rhynia. In Asteroxylon axes, this ratio is about twice as large as in Rhynia axes. (4) Contrary to the expectations, the distance between the outermost layer of the xylem and the transpiring surface, which represents the low-conductivity pathway through the parenchyma, appears not to be a limiting factor for the water transport in axes of Rhynia and Asteroxylon. (5) From the analysis of the geometric parameters, it is evident that Rhynia and Asteroxylon with their distinct stelar geometries represent two different constructional types for which no transitional stages are known.

Specificity in calcium oxalate adherence to papillary epithelial cells in cultures

1988 ◽  
Vol 255 (5) ◽  
pp. F1025-F1032 ◽  
Author(s):  
R. J. Riese ◽  
J. W. Riese ◽  
J. G. Kleinman ◽  
J. H. Wiessner ◽  
G. S. Mandel ◽  
...  
Keyword(s):  
Calcium Oxalate ◽  
Specific Binding ◽  
Primary Cultures ◽  
Sectional Area ◽  
Cross Sectional ◽  
Culture Area ◽  
Monolayer Growth ◽  
Collecting Tubule ◽  
Dependent Inhibition ◽  
Ap Value

Attachment of microcrystallites to cellular membranes may be an important component of the pathophysiology of many diseases including urolithiasis. This study attempts to characterize the interaction of calcium oxalate (CaOx) crystals and apatite (AP) crystals with renal papillary collecting tubule (RPCT) cells in primary culture. Primary cultures of RPCT cells showed the characteristic monolayer growth with sporadically interspersed clumped cells. Cultures were incubated with [14C]CaOx crystals, and the crystals that bound were quantified by microscopy and adherent radioactivity. Per unit of cross-sectional area, 32 times more CaOx crystals were bound to the clumps than to the monolayer. CaOx adherence demonstrated concentration-dependent saturation with a beta value (fraction of cell culture area binding CaOx crystals) of 0.179 and a 1/alpha ox value (maximum micrograms of crystallites adhering to 1 cm2 of binding area) of 287 micrograms/cm2. On coincubation with AP crystals, CaOx binding demonstrated concentration-dependent inhibition with a 1/alpha AP value of 93 micrograms/cm2. Microcrystallite adherence to RPCT cells demonstrates selectivity for cellular clumps, saturation, and inhibition. These features suggest specific binding.

Numerical studies of water conduction in land plants: evolution of early stele types

Paleobiology ◽  
1996 ◽  
Vol 22 (3) ◽  
pp. 411-421 ◽  
Author(s):  
Anita Roth ◽  
Volker Mosbrugger
Keyword(s):  
Transport Properties ◽  
Water Transport ◽  
Vascular Tissue ◽  
Plant Evolution ◽  
Cross Sectional Area ◽  
Functional Explanation ◽  
Sectional Area ◽  
Cross Sectional ◽  
Water Conduction ◽  
Water Transport Properties

During land plant evolution, a change in stelar architecture, i.e., in the geometric arrangement of the water-conducting tissue inside the plant axis, can be observed. In the most primitive stele type, the protostele, the vascular tissue is organized as a simple central strand. Further evolutionary changes led to more peripherally arranged vascular tissues. In the siphonostele, for example, the vascular tissue forms a hollow cylinder filled with pith. A functional explanation of this early stelar evolution is provided in the present paper. Using a numerical simulation approach, we analyze the water transport properties of various protostelic and siphonostelic model axes. The results indicate that several geometric parameters are relevant for understanding the water transport properties of various stele types and for explaining the early stelar evolution: the parenchymatic path lengths (i.e., the distance between the xylem surface and the transpiring plant surface), the ratio of xylem surface over transpiring surface, and the ratio of cross-sectional area of xylem to cross-sectional area of the parenchyma outside of the xylem. As a whole, the evolution of early stele types may be viewed as a size-related multi-criteria optimization process in which the xylem volume as well as the fluid pressure gradients in the parenchyma and in the xylem are minimized. For slender plant axes, a protostele appears to be the optimal stelar architecture. In wider plant axes, however, other stelar architectures (such as a siphonostele) prove to be more efficient than a protostele.

scholarly journals The Phloem of the Wheat Stem in Relation to Requirements for Assimilate by The Ear

1970 ◽  
Vol 23 (4) ◽  
pp. 743 ◽  
Author(s):  
LT Evans ◽  
RL Dunstone ◽  
HM Rawson ◽  
RF Williams
Keyword(s):  
Light Intensity ◽  
Wild Species ◽  
High Light Intensity ◽  
High Light ◽  
Cross Sectional Area ◽  
Main Stem ◽  
Vascular Bundles ◽  
Sectional Area ◽  
Cross Sectional ◽  
Related Wild Species

The cross-sectional area of the phloem and the number of vascular bundles at the top of the main stem were determined in 22 diploid, tetraploid, and hexaploid wheats and related wild species grown at 21{16�C in 16-hr days of high light intensity.

scholarly journals Evaluation of the Possibility of Performing Cold Backward Extrusion of Axisymmetrical Thinwalled Aluminum Die Stampings with Square Section / Ocena Możliwości Wyciskania Przeciwbieżnego Na Zimno Osiowosymetrycznych Wyprasek Z Cienką Ścianką O Przekroju Kwadratowym Z Aluminium

2015 ◽  
Vol 60 (4) ◽  
pp. 3043-3050 ◽  
Author(s):  
T. Miłek ◽  
B. Kowalik ◽  
B. Kuliński
Keyword(s):  
Mechanical Properties ◽  
Flow Curve ◽  
Computer Modelling ◽  
Cross Sectional Area ◽  
Experimental Investigations ◽  
Sectional Area ◽  
Cross Sectional ◽  
Industrial Practice ◽  
Backward Extrusion ◽  
Thin Walled

The paper presents evaluation of the possibility of performing cold backward extrusion of axisymmetrical thin-walled aluminum (Al 99.50, ENAW-1050A) die stampings with a square section at the strain ε=ln(A0/A1)=2 (where A0 - cross sectional area of the billet, A1 - cross sectional area of the die stamping), and the ratio h1/b=3.6 (where h1 - height of the die stamping in mm, b - width of the base of the die stamping in mm). The analysis was conducted on the basis of the results of computer modelling (FEM) and experimental investigations on backward extrusion. The boundary conditions for numerical calculations were determined experimentally with respect to the flow curve and mechanical properties of aluminum. The results of investigations into backward extrusion of thin-walled square-sectioned aluminum die stampings might be used as guidelines to develop a technological process for industrial practice.

scholarly journals Ultrasonographic evaluation of the posterolateral radiohumeral plica in asymptomatic subjects and patients with osteoarthritis.

2015 ◽  
Vol 17 (2) ◽  
pp. 155 ◽  
Author(s):  
Fatih Celikyay ◽  
Ahmet Inanir ◽  
Erkal Bilgic ◽  
Zafer Ozmen
Keyword(s):  
Clinical Characteristics ◽  
Morphological Features ◽  
Cross Sectional Area ◽  
Control Group ◽  
Study Group ◽  
Sectional Area ◽  
Cross Sectional ◽  
Radiographic Findings ◽  
Elbow Osteoarthritis ◽  
Asymptomatic Subjects

Aims: The aim of this study was to describe the morphological features of posterolateral radiohumeral (RH) plica in asymptomatic subjects and in patients with elbow osteoarthritis using ultrasonography (US). Material and methods: The control group included a total of 100 healthy elbows (51 subjects) and the study group consisted of 22 elbows (22 patients) with osteoarthritis confirmed clinically and by imaging methods. The presence, length, height, thickness, cross sectional area, shape, and echogenicity of the posterolateral RH plica were evaluated in both groups. In addition, humeral and radial cartilage thicknesses were also measured. The clinical characteristics and radiographic findings of the study group were evaluated. Results: The posterolateral RH plica was present in all elbows of the control group (100%) and in 15 (68%) of elbows in the study group (p0.05). Conclusions: The posterolateral RH plica can be successfully evaluated using US. Based on these findings, it appears that osteoarthritis can result in a reduction of sizes of the RH plica and affect its morphological appearance.

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